While in mid-ride 2nd gear 5 grand, she sputtered out and died, was able to pop start it to get her home and rode once more to work, store, and back, but hasn't been able to start up since.

So after some reaserch on this forum and digging through the manual, and the urge to take it apart to get a good idea of what the condition under the plastics were, I decided to buy a FPR and a fuel filter without diagnosing the issue first. $100 elimination of a potential problem.

Turns out the FPR didn't leak but replaced it anyway as I believe it was factory. And installed the fuel filter. Didn't bleed the tank and clean the lines yet, but that's next.

I have the bike almost completely dissasembled as I will post in a picture.
And the next step is checking spark.
Also upon opening the airbox I noticed one of the air filters was "crushed" slightly and filthy on the inside. Will replace for peace of mind when finances allow.

I documented the process on video and intend to put on youtube hopefully with a [SOLVED] ending. If not also for educational purposes.

Assuming the previous owner told me the truth and the sparks were replaced during a pre sale tune-up, and they are not the issue, then I will have had crossed out 2 of the 3 factors that require an engine to run. Leaving me with combustion. The one day I had taken it to a dealer one of the techs had pointed out she was running a little rough, (valve adjustment) and also informed me that the symptoms I had described could be the result of my valves not getting proper clearance. I have to keep in mind that I live in phoenix and it is summer and V-twins run hot enough as is. So this is a possibility although an expensive procedure that might not even be the case.

Anyway, I thought I'd tell my life story to put all the cards on the table in hopes someone may recognize anything that might help my situation.

Any and all feedback is greatly appreciated! Thanks for taking the time to read this.

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I don't have a PC installed. And I did a pretty thorough check on the wiring (not very electrical savvy though) and the battery is new and fully charged (but at a 45 degree angle because of the funny wiring business) and she cranks over no problem, sound like shes choking on not enough fuel though.

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So im just posting these, but I realized its not a fueling problem. I have no spark from my plugs and im attempting to remove my coil. Unfortunately I just realized the service manual I d/led was of 00-02, so not the right dissasembly procedures. Going to find my model and go from here.

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So upon removing the coil (not the easiest job) and testing the resistance, it's reading .6 ohms which I imagine is no where near the reading it should be. I can't find specs on what the coil specific to my bike should be, and the dealership is closed today and labor day tomorrow. Sooo... yea. It's very possible its my coil because the spark plugs aren't getting any current through it.

It's getting dark and as you can tell I don't have a garage so I will be back in a couple of days...

Thanks for the replies.

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Super Moderator

An ignition coil is essentially a step-up transformer.
So the low voltage/high current primary side won't have much resistance since it has fewer windings than the low current/high voltage secondary side.

Misfires can come for internal coil windings breakdown (usually when the coil gets warmed up), broken conductor in the plug wire, broken insulation of the plug wire causing shorts to chassis ground, loose fitting plug cap, etc.
If both cylinders are affected, it could possible be a failing pulse generator sensor, or the ignition converter (CDI box).

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So after checking/cleaning all connections and "cleaning" out the gas tank, I've figured out it was more than likely a fuel delivery issue and what also may be contributing, very dirty K&N air filters. Running a fresh tank with the new components and a shot of starter fluid, she started right up. Tomorrow I will be getting OEM filters, with the hope of a solved problem. (These are the conditions the filters were in)

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The Svc Manual you downloaded is the right one. You can get all the specs and descriptions you need from it. It says 2000- 2002 because that's the only years there were any changes and it covers those changes.
Did it come from Saltair or RC51info? Either way, those are the correct manuals.
Sounds like you've become intimately familiar with your bike this weekend, that's always a good thing. Those filters look like SHITE! Seems like that alone would cause your symptoms. Good luck, I hope that's all it is.
I'm curious, how did you come to the conclusion that you're getting no spark to the plugs? Are you getting fire to them now?
Poor bees, I got part of a dragonfly if your bees want some company...

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I think I got it off here somewhere. But oddly enough it had said the coil was behind the right radiator but it was behind the left, so thats what threw me off, glad to know it is for my model.

In a sense I'm kind of glad she died on me because that was more than enough motovation to strip it down to really get to know everything on the bike.

Another thing that kind of ticked me off about the filters was that they were both the same size and they had crushed one of them to get it to fit (not something I would ever fathom to be an option)

The spark was fine, I had blown my spark tester while trying to get a reading lol.

I have OEM filters on their way this week so I wont know how she preforms on a ride until I get those, but all in all after I put some gas in the tank, add more coolant, (lost a lot taking the radiator off) and reassemble the bike, I'm pretty confident that she'll fire right up and be good as new. *fingers crossed* *knock on wood* *rub Buddha's belly*

The front coil is mounted on the left frame spar on the SP2 (which is your model). The coil is on the right for the SP1.
When reading the combined SP1/SP2 service manual, make sure that section is referring to the SP2 ("after 01" in the service manual).
While both models appear similar in many ways, always refer to the "after 01" areas for your bike.

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Well then... so last night I got her to fire up no problem, still dont have the filters yet though. I took her out today and it's about 106° out, and boy did she run HOT! I took her to the dealership where I've been getting in pretty good with the techs, to show it off and let them hear it. Right off the bat they noticed how loud it was (overbearing the belt driven cams) which had me concerned, and they said a valve adjustment should alleviate that issue. Also upon contacting the original owner's shop to see the history, they informed me about a mod they did which was "removing some springs on the cam gears" (I would love to know more about this and especially the downsides to this mod if anyone knows of it)

Anyways, I left the dealership and went down the highway to do a little test ride, got on it a little bit but nothing serious, and really noticed the power wasn't quite there like I remember it being. On the way back home upon getting on my exit ramp I rolled off the throttle and she died! Mind you it was very hot out and the bike temp reached 242° while still having momentum I tried to pop start it, no luck, by this time when I turned the run/cycle switch I finally heard the oil fans, I couldn't hear them on the highway which concerned me, not sure if I would be able to on the highway, but they are loud. So I'm almost worried about an overheating problem, but I "pretty much" flushed the cooling system but didn't check the thermostat, pretty sure it works well.

So I pushed it home and it's in the driveway cooling off...

Back to square 1... I will figure this out if it kills me and my pockets I solemnly swear it.

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Yeah, those filters are complete toast!
Sounds like your dealership wants a nice valve job in their shop.
When it's that hot outside, your bike wont run as powerful as when it's in the 60's or 70's. And you could probably feel the difference.
251F degrees is the meltdown point. If I saw 245, I'd shut her down and let it cool.
You might have an air bubble in your cooling system? Have you tried burping it?
You can get a good clue if your thermostat is opening at the right temp when you burp the rads also.

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What melts down exactly? Because last night I went on a ride to make sure it ran smooth but like an idiot I forgot to refill the radiator, so it was half empty, and after 10 minutes the temp light came on and so did the temp with a 260°-270° reading. Killed it and let it cool way off before quickly returning home. Could I have had suffered some permanent damage?

I don't think I may have done a great job at burping now that I think about it

Super Moderator

These bikes (like most these days) run close piston to cylinder clearances.
Most likely what will happen if the temps exceed 251 deg F (or more) for an extensive period could be piston scuffing or seizure, and also warping of the cylinder heads.
Both requiring an engine rebuild or replacement. Not good or cheap.

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Hi Friends,
I started riding 60 miles each way to work on the highway last week. My RC won't shift up into 5th or 6th. What could the root cause be and am I looking at an expensive repair? Also my local shops seem really backed up, do I risk any damage by continuing to ride it 120 miles...

.....for the red and black/silver model RC51? Does anyone know the original Honda codes so I can have it matched as close as possible? I think I really only need the silver and red to repair the top/side of the tank.
Thanks for your help

Noticed that there is fluid slowly weeping from this area on the clutch slave cylinder. I am going to say this needs a rebuild. I guess I am looking at a leaking piston seal? Any advice appreciated. First time dealing with a hydraulic clutch. My other bikes are cable operated.

I have a 02 rc51,it’s been sitting 15 yrs ... decided to get it running 🤷🏻‍♂️
cleaned fuel tank, replaced fuel pump with a quantum pump and filter...
Put tank back on and even with the fuel pump unplugged, the bike floods out and cylinders fil with fuel
Any one help 🤷🏻‍♂️

Has anyone deleted the airbox and ran filters straight off the throttle bodies? Does someone make adapters for clamp on filters? What did you do with your sensors? Curious because the cart I’m building won’t be using the intake tube or airbox. Thank you